"With what we have got, 11 countries from non-OPEC together with us in OPEC, we have not closed the collaboration. We expect other non-OPEC countries to join us, including the United States," Barkindo said.
On Saturday, OPEC and 11 non-OPEC countries struck a historic deal for the latter to reduce oil output by 600,000 barrels per day in the wake of the November 30 OPEC agreement in Vienna to cut production by 1.2 million barrels per day.
The summary cut amounts to some 1.8 million barrels per day in the first half of 2017. The deal finalized a preliminary agreement reached in Algeria in September.
The 11 non-cartel states which agreed to the deal included Russia, Azerbaijan, Bahrain, Brunei, Equatorial Guinea, Kazakhstan, Malaysia, Mexico, Oman, Sudan and South Sudan.
